You are almost turning it into a sensorless motor, there are still a few differences you should be cautious of.

First, sensored motors are usually wye wound, while most sensorless are delta wound. A wye type motor, of relatively high resistance (lower Kv), will not normally exhibit good startup quality on a sensorless controller. I think most people like myself have decided that anything slower than a 10.5 is not a good match with a sensorless controller. However......

Secondly, sensored motors come with increased timing on the motor, while sensorless type motors usually will be fixed at zero timing, as it is controlled thru the ESC. Luckily, Viper was honest and smart in choosing to have the timing value listed on the can as the actual amount. Some manufacturers build a certain amount into the windings, then add additional timing into the adjustment. I am not sure if it is true or not, but I read that Novak motors have 30* built into the motor, meaning that when you have the value on the can at zero, you are actually getting 30* already, with no choice to turn it down. Compared to a zero degree sensorless motor, any sensored type motor is going to have a significant amount of increased timing, and this can also lead to poor startup quality or even motor failure in extreme cases.

Knowing this, I would make sure to set the motor timing as low as possible. The marks go down to 15* on the Viper, and I would probably try to go a little lower than that within reason. And if you have something like a 17.5 or even 13.5, I would not expect super smooth starts, but it should run just fine once up to speed. Dont forget that ESC settings like start power or timing can also improve or worsen your low speed operation, so dont be afraid to try them if you need to change anything. So to answer your question, I dont see any reason not to switch any two wires like you would with a sensorless motor. The sensors require the ABC orientation and can cause serious problems when it is not correct, but without them it is essentially like a sensorless motor, as the previous reply stated.